Reclassification of Brevibacterium frigoritolerans DSM 8801 as Bacillus frigoritolerans comb. nov. Based on Genome Analysis.

16S rRNA gene sequence analysis showed that the type strain Brevibacterium frigoritolerans DSM 8801 had the highest similarity (99.7%) with the reference strain Bacillus simplex NBRC 15720, followed by Bacillus muralis DSM 16288 (99.6%), Bacillus butanolivorans DSM 18926 (99.5%), and Bacillus loiseleuriae FJAT-27997 (97.9%). This relationship is confirmed by the phylogenetic analysis indicating that Bre. frigoritolerans DSM 8801 fell in the genus Bacillus group and formed a clade with the closely related Bacillus species. Average nucleotide identity and in silico DNA-DNA hybridization (isDDH) values between strain DSM 8801 and the most closed reference strain Bac. simplex NBRC 15720 were both much lower than species definition threshold values of 95% and 70%, respectively, which indicated strain DSM 8801 should not be affiliated to one of the validly named Bacillus species. The percentage of conserved protein (POCP) values between the strain DSM 8801 and the type strains of the above species were 80.7%, 69.2%, 72.2%, 53.6%, and 50.0%, respectively, higher than the genus definition threshold value of 50%. The main isoprenoid quinone of strain DSM 8801 was MK-7, the main polar lipids were diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), and phosphatidyl ethanolamine (PE), and the major fatty acids were anteiso-C and iso-C. On the basis of the phenotypic, chemotaxonomic, phylogenetic and genomic characteristics, Bre. frigoritolerans DSM 8801 should belong to the genus Bacillus, and be proposed to reclassify as Bacillus frigoritolerans comb. nov., with the type strain DSM 8801 (=ATCC 25097 = CCUG 43489= CIP 67.20= JCM 11681).